Karnataka Veterinary Medical Officer Course Animal Nutrition Unit 4 Animal Nutrition

Lesson 1, Topic 4

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Unit 4 Animal Nutrition

ajmi bin azeez August 20, 2024

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Feed Technology, Feeding Experiments and Standards

1. Processing of Concentrates

2. Processing of Roughages

3. Feeding Experiments

4. Feeding Standards

5. Conservation of Feed through Silage and Hay

1. Processing of Concentrates

Objectives of processing feeds are-

To alter the particle size (most imp factor)
To change moisture content
To change the density of feed
To increase nutrient availability
To change acceptability (palatability)
To detoxify/remove harmful ingredients
To improve keeping qualities
To make the storage easy and safe
To make animal production more economical

1. Processing of grains method-

1. Wet processing methods: soaking, steamrolling, reconstitution, exploding, gelatinization, pressure cooking

2. Dry processing methods: grinding, dry rolling, crimping, crumbles, popping, micronizing, roasting, extruding, pelleting, decortication.

Processing of grains/cake

1.1 Wet processing methods:

Soaking: Grains are soaked in water for 6 to 24 hours prior to feeding. Soaked grains soften, swell and become more palatable. They are easy to mix with roughages and reduce toxic factors.
Reconstitution: water is added to dry grain (10%) to raise the moisture content to 25-30% and then stored in an oxygen limiting silo for 2-3 weeks prior to feeding. It increases the solubility of the grain carbohydrates and protein.
Steam rolling/ Crimping: expose grain to steam for a short period to soften the kernel followed by rolling/compressing. Availability of starch is increased.
Extrusion: cooking with the application of adequate pressure to expand the feeds is called extrusion. It results in gelatinization of starch.
Exploding: swelling of grains subjected to high pressure steam (250 psi) for 20 seconds followed by sudden decrease to atmospheric pressure in steel vessels .
Pelleting (moist): Densification of grain with steam or moisture. Pelleting reduces the dustiness of feed, increases the palatability, and makes it easy to handle large particles.
Gelatinization: Complete disintegration of starch granules of grains by application of moisture, heat and pressure is known as gelatinization. It improves the digestion of feed by action of amylase on soluble carbohydrates.

1.2 Dry processing methods of grains:

Grinding: least expensive method of reducing particle size. It breaks the outer layer exposing the starch and increases the surface area exposed to enzymes. Fine grinding 🡪 increase dustiness and reduce digestibility. Machine 🡪 hammer mill which reduces the particle size of grain until it passes through a screen of suitable size (1 or 2 mm).
Dry Rolling: compression without adding moisture by passing it between moving rolls. It is a combination of breaking and crushing.
Crimping: process of rolling of feed ingredients with the use of corrugated rollers is called crimping.
Crumbles: breaking of pelleted feeds is called crumbles.
Popping/ puffing: application of dry heat (370-425⁰C) for 15-30 seconds causing a sudden expansion of the grain which ruptures the endosperm/starch granules making it more available for digestion.
Micronizing: popping of grains with the application of infra-red heat energy having wavelengths of 3×10⁸to 3×10¹¹ cycles/second.
Roasting: Dry heat processing of the grains with direct flame (300^oF) is called roasting. Roasting of whole soybeans inactivates enzymes or inhibitory factors, which improve its nutritive value.
Decorticating /dehulling: It is the process of removing the outer coat of grains having high fibre and low digestibility. It improves the energy and protein content of the grains.
Extruding: Thermo-mechanical process in which the grains are cooked under high pressure with high temperatures for a short time.
Pelleting (dry): It is agglomerating of feed by compacting and forcing it through die opening by a mechanical process without application of steam/moisture.

Advantages of pelleting are:

Improved handling, storage and other handling characteristics
Less wastage of feed
Allows combination of several ingredients or formation of complete ration
Increases feed density and reduces storage space
Improving nutritional value through instantaneous heat and pressure.

2. Processing of Roughages

1. Physical processing of roughages

a. Dry processing methods

b. Wet processing method

2. Chemical treatment/processing

3. Biological processing of roughages

2.1. Physical processing of roughages

Dry processing methods
1. Dehydration: reduction of moisture content in a dehydrator using a temperature 600-1500^oF for 3-5 minutes. carotene content is reduced by 5-15% by it.
2. Baling: forage is cut, dried and then bundled with baler for making storage and handling of forage easy and convenient.
3. Chopping/ chafing: chopping with a chaff cutter for easy handling due to increased bulk density. It also improves ruminal digestion of fiber due to increased surface area. Chopping avoids selective feeding thus wastage of plant material is reduced. Chopping to the average particle size of 0.25- to 0.50 inch appears to be optimum. Too much smaller particle size may adversely affect fat content of milk.
4. Grinding: reduces particle size. Fine grinding of less than (0.25) 1/4^th inch, reduces the transit time and decreases rumen contractions, pH, VFA production and salivary secretion.
5. Pelleting: ground feed compressed to 1/4 to 3/4′ inch in diameter and 1/4 to 1.5 inch in length and a density of 18-20 kg/cft. Finely ground fodder plants are not generally pelleted because the fine particle size affects the normal rumen functions by reducing time of mastication, salivary secretion, lowering of rumen buffering and thereby, decreasing rumen pH. It also increases the rate of fermentation and reduces rate of feed passage through GIT.
6. Cubing/block and wafering: highly compressed forage made from long or coarsely chopped material by heat and pressure. Advantages: increased consumption and production, saving in labor cost, less feed wastage.

Wet processing:

Soaking: mixing or spraying water on roughages to soften the stem to improve its palatability and mix the concentrates uniformly which improves the feed intake and digestibility of roughages.

2.2 Chemical treatment of roughages

Treated with chemicals such as sodium or potassium hydroxide and urea to increase the availability of the nutrients to livestock.

i. Urea treatment: Urea treatment is most economical and easiest.

Method: 4 kg urea dissolved in 40 litres of water and sprayed over 100 kg of straw.

Urea hydrolysis by urease: Ammonia 🡪 breakage of lignocellulose bond by ammonia thereby releasing cellulose from lignin bondage for digestion and utilization.
After 21 days the urea treated paddy straw is ready for feeding.

Advantages:

Increase the CP and TDN content from 2% to 10% and 45 to 60%, respectively.
It improves the palatability.
Special consideration while feeding urea treated straw:

Not advisable to feed the urea treated straw for calves below 6 months of age.
Adaptation period is required.
NaOH treatment: 1.2-1.5% sol.🡪 Beckmann’s method.

ii. Ca(OH)₂+ NaOH treatment: both 4%.

iii. 3% Anhydrous NH₃: bind with sugar 🡪 4-methylimidazole (cause Bovine bonker)

2.3. Biological processing of roughages

Enzyme treatment: Cellulase improves cellulose digestibility (25 mg/100 kg straw).
White-rot fungi, mushrooms and other microbes: Some of the white-rot fungi like Phanerochaete chrysosporium degrade lignin to the extent of 65-75% while other fungi like Ganoderma applanatum and Coriolus versicolor degrade over 45% of lignin in the lignocellulosic straws.
Indo-Dutch project on bioconversion of crop residues is a bilateral project of the governments of India and the Netherlands use of fibrous crop residues as animal feed by using on white-rot Basidiomycetes, often belonging to the non-toxic and edible mushrooms.
Zadrazil process: Straw was treated with Pleurotus spp (mushroom). This process causes enormous losses of organic matter and therefore is not fit for small level operations.
Karnal process: two-stage technique.

In first stage, cereal straws are treated with 4% urea and 40% moisture and ensiled for 30 days followed by
second stage in which the urea treated material is mixed thoroughly with 1% single superphosphate, 0.1% calcium oxide and then moisturize to 60-65% before inoculation with 3% Coprinus fimetarius (alkali tolerant fungus strain) culture grown on millets.
The solid substrate fermentation is terminated at the mycelial stage of growth of C. fimetarius.

3. Feeding Experiments

3.1 Importance of Feeding Experiments:

Give knowledge of quantitative need of nutrients
Information has been gained through feeding experiments/ trials and experience

3.2 Different methods of feeding experiments in livestock

The art of feeding animals was originally developed by trial and experience. Most useful method of obtaining results which have a direct application to feeding practice.

1.Comparative feeding trials

Two or more rations may be compared with growth and production.

In case of two rations, ‘t’ test is used while in case of three or more rations ‘analysis of variance test is applied to analyze the data like feed consumed per day, average daily gain (ADG), feed consumed per kg gain (feed efficiency) etc. for statistical significance.

2. Feeding trials with laboratory animals ( like rats, mice, hamsters etc.)

Advantages

Low cost and the shorter time
Individual variability can be reduced
Very easy to slaughter lab animals

3. The purified diet method

Purified diets were used in conducting feeding trials with lab animals.
Purified diets consist of purified sources of the various nutrients.
For example

Carbohydrates is supplied as starch, glucose or sucrose
Protein is supplied as Casein, Purified soybean, urea
Fat as lard or some oil
Minerals a chemically pure salts
Vitamins as pure crystalline compounds

3.3 Experimental designs

Feeding trials are set up in such a way so as to allow statistical analysis for experimental designs

Completely Randomized Design (CRD)
Randomized Block Design (RBD)
Latin Square Design (LSD).

1. CRD: Treatments are assigned completely at random so that each experimental unit has the same chance of receiving any one treatment.

2. RBD: Experimental units are grouped into blocks, with the different treatments to be tested randomly assigned to the units in each block. Data analysis is simple and easy to understand.

3. LSD: Experiments to minimize the number of animals required to detect statistical differences.

3.4 Methods adopted for Digestibility of nutrients

1.1 Norms for Conducting Digestion Trials

Major loss of feed energy: undigested food i.e. feces
Digestibility trial to assess this loss
Digestibility: portion of feed nutrients not recovered in feces (as % Digestibility coeff.)
Dig (%) = (Amt. of nutrient in feed eaten – amt. of that nutrient in feces) x100 /Apparent Amt. of nutrient in feed eaten
True digestibility (%) = Amt. consumed – (fecal excretion – metabolic loss) x100 Amt. consumed
Dig. Coefficient is estimated for organic matter only.
Ash/mineral: no energy, main excretion is through feces so metabolic loss is high.
So the isotope (labeled) method is used for mineral absorption.

3.5 Measurement of Digestibility

In-vivo methods:
1. Direct in-vivo method
  1. By digestion – only feces collection – ruminants
  2. By metabolism trial – feces and urine (and milk in milch animals) both collection – poultry

Norms of trials:

Animals: homogenous, four (minimum), male are preferred (collection of urine and feces easy)
Preliminary period: 7-14 days in ruminants and 2-5 days in pigs.
Collection period: 5-7 days (7-10 days sometime)
Indirect in-vivo method:
1. By Difference: difference of nutrient intake and fecal excretion is considered.

Maintenance ration: one trial is conducted. Ration that maintains constant BW is given and dig. is estimated.
Productive ration: 2 digestion trials (e.g. concentrate) are conducted.
1. Trial 1 = (maintenance ration) and
2. Trial 2 = (maintenance + production ration).
3. So, Dig% = (Trial 2 – Trial 1).
Non-maintenance ration : 3 digestion trial (e.g. wheat straw)

Trial 1 = (maintenance ration)
Trial 2 = (maintenance + production ration)
Trial 3 = (Non-maintenance + production ration)
Dig% = Trial 3 – (Trial 2- Trial 1)

Drawback of difference method:

1. Associative effect of feeds:

Addition of productive ration (protein cake/ grains) may influence digestibility of basal/ maintenance ration or non-maintenance ration (wheat straw)

2. Digestibility in poultry:

• By surgical mean: separate urine and feces

• By chemical method: Urine N- uric acid and Fecal N – true protein

b. By Indicator/ markers: inert reference substance

• Ideal marker:

totally indigestible and non-absorbable
no pharmacological action on GIT (inert)
mix intimately and uniform distribution
uniform rate of pass through tract even a small amount of feces collected at any time gives an amount of nutrient per unit of marker.
voided completely
can be determined chemically in feces
natural constituent of feed – preferable

Indicator
Internal	External
Natural constituent of feed	Not natural constituent of feed
Lignin	Chromic oxide (Cr2O3)
Silica	Ferric oxide
Acid insoluble ash	Radioactive isotopes: Cr51, Ce144

Digestibility of a nutrient is calculated by estimating the concentration of the marker and

the nutrient in the feed and feces.

• No need for quantitative collection of feces and feed consumption.

Dig% =

100 – {100 x (%indicator in feed/%indicator in feces) x (% nutrient in feces/% nutrient in feed)}

• But, recovery of marker is not 100% (chromic oxide: 94%)

• So, revised formula:

Dig% =

100– {100 x (% recovery x %indicator in feed/%indicator in feces x % nutrient in feces/% nutrient

In feed)

Estimation of Feed intake in grazing animals

• Tendency of selective grazing pasture can’t be studied in stall

• Marker method for grazing animals: Digestibility= internal indicator (lignin)

Fecal output= external marker (Cr2O3)

Chromic oxide capsule – fed and then sampling at different intervals to know avg. conc per unit of feces.

Feces output: Marker consumed (g/d)/Marker conc. (g/g feces)

Digestibility % = 100 – % Indigestibility = (intake – output/intake x 100)

Intake: (Output/% Indigestibility) x 100

B. Laboratory:

1. in sacco / semi in-vivo method/ in-situ technique

• Only ruminal digestion is considered followed by laboratory analysis (lower tract dig. not taken)

• Fistulated animals: at least 3

a. Bag technique:

• Bag : nylon, dacron or silk – kept in rumen

• Important parameters of in sacco method:

Bag size: 6.5 x 14 cm (may be larger)

Porosity of bag: 40-60 μm

Feed particle size: 1-2 mm

Sample size to bag surface area: 10-20 mg/cm2

Limitation: effect of mastication, rumination and transit not considered

b. VIVAR technique: in-vivo artificial rumen. It is a porcelain test tube/ stainless steel tube separated by a semi-permeable/ bacteriological membrane from the rumen liquor.

Limitation of semi-in vivo method: effect of mastication, rumination and transit not considered.

Factors that affect the degradability of feed in nylon bag technique:

Particle size- since the test feed kept in the bag has no chance neither for mastication nor for rumination. The test feed sample should be ground through 1-2 mm screen.
Bag porosity- a porosity of 40-60 um has been found to be optimum.
sample size to bag surface ratio- 10-20 mg/cm2 is recommended.
Diet of the animal- basal diet should contain small amounts of a wide range of ingredients to establish a diverse microbial population apart from the test feed sample.
Bags per animal
Animal species
Numbers of animals- 3 fistulated animals are required at least.
Number of replicate bags per animal per incubation time
Positioning of bags in the rumen
Incubation length-depend on the type of the feed
Timing of bag introduction in the rumen and pre ruminal soaking

2. in-vitro rumen fermentation technique

1. One-stage technique: feed + rumen liquor + artificial saliva – 39oC / anaerobic condition

2. Two stage technique: 1st stage: rumen fermentation foregut digestion

2nd stage: acid- pepsin solution hindgut digestion

Important Facts

• In-vitro gas production system : Menke and Steingass (1988) Menke’s method

• VIVAR technique: in-vivo artificial rumen semi-permeable membrane

• Drawback: feed intake, palatability not considered

• Use of in-vitro rumen fermentation technique:

: Rapid screening of large no. of samples

: Evaluation of newer/ unconventional feeds

Drawback of in-vitro technique: feed intake, palatability and associative effects of feed ingredients not considered

3.6 Factors that affect the digestibility of feeds

They can be grouped as

A. Animal Factors.

B. Plant factors.

C. Feed Preparation.

A. Animal Factors:

1. Species of the animal-

Roughages high in CF are better digested by ruminants than by non-ruminants due to the pre-gastric rumen fermentation that occurs in the former.
Non-ruminants post -gastric fermentative digestion occurs which helps in the digestion of CF.

released are digested and absorbed in the stomach and small intestine.

2. Age of the animal- very young and very adult animals are usually less efficient in their digestion of feeds.

3. Work – Light exercise or work increases the digestibility while heavy exercise or work decreases the digestibility.

4. Individuality- individual variation of as much as 25 % has been reported.

5. Level of feeding- High level of intake decreases digestibility as rate of passage is increased.

B. Plant factors: Chemical compositions of feed

1. Generally, grains are well utilized by all classes of livestock.

2. Feeds higher in protein give higher apparent digestibility of protein because MFN output depends on the amount of feed consumed and not on the amount of protein consumed.

4. Feeding Standards

Feeding standards are statements or quantitative descriptions of the amounts of one or more nutrients needed by animals.

Requirement is expressed in quantities of nutrients required per day or as a percentage of diet.

Objectives of feeding standards:

To guide farmers to formulate properly balanced rations for their livestock.
Estimate the adequacy of feed/ nutrient intake for various spp. of animals.
To classify the nutrient requirement according to different physiological functions like growth, maintenance, lactation, egg production and wool growth.

Limitation of feeding standard:

No standard can be a complete guide to feeding because some other factors like palatability and physical nature of ration can play significant roles.
Environmental conditions

Expressions of nutrients requirements in different standards are DE, ME, NE, TDN, CP, DCP, MP.

Classification of feeding standards

Feeding standards
A. *Comparative type*	B. *Digestible- Nutrient system*	C. *Production-value type*
Compare different feeds to a standard one	Feeding based upon digestible portions of nutrients in different feed.	Based upon efficiency offeed to increase productivity.
1. Hay standard2. Scandinavian feed Unit” Standard	1. Grouven’s Feeding standard2. Wolff’s feeding standard3. Wolff’s Lehmann feeding standard4. Haeckers’s Feeding standard5. Savage feeding standard6. Morrison standard7. National Research Council standard8. Indian standard	1. Kellner-feeding standard2. Armsby feeding standard 3. Agricultural and Food Research Council standard.

A. COMPARATIVE TYPE

1. Hay standard: suggested by Thaer In 1810

Different feeds should be compared using meadow hay as a unit.
The only measure was the practical feeding experience.
Nothing was known of the chemical value of feeds and the physiological requirements of the animals.

2. Scandinavian “feed unit” standard: By Professor Fjord In 1884

only the feed unit was taken.
The value of one pound of common grain such as corn, barley or wheat, is given as one unit value and the value of all other foods is based upon this.
According to this standard, one feed unit is required for each 150 lbs. of body weight and an additional unit for every three pounds of milk production.

B. DIGESTIBLE NUTRIENT SYSTEM

1. Grouven’s feeding standard

Feeding standard with crude protein, carbohydrates and fat contained in the feed as the basis of the standard.
According to this standard, a cow weighing 1,000 lbs. should be fed 28.7 lbs. of dry matter containing 2.67 lbs. of crude protein 0.6 lb. of crude fat and 14.55 lbs. of crude carbohydrates.

2. Wolff’s feeding standard: by Dr. Emil Von Wolff In 1864

Based on digestible protein, digestible carbohydrates and digestible fats.
This standard is an improvement over the standard of Grouven,
It does not consider the quantity and quality of milk produced.

3. Wolff’s Lehmann feeding standard:

Dr. G. Lehmann of Berlin modified Wolff’s standard in 1896.
He took into account the quantity of milk produced, but he failed to take into account the quality of milk.

4. Haecker’s feeding standard

First time considered the quantity as well as the quality of milk produced in formulating a milk standard.
First to separate the requirements for maintenance from the requirements of production.
His standards included digestible crude protein, carbohydrates and fats.
Later it was expressed in digestible crude protein and total digestible nutrients.

5. Savage feeding standard

Based on nutritive ration
The nutritive ratio should not be wider than 1:6 or narrow than 1:4.5.
About two-thirds of the dry matter should be from the roughages and one-third from the concentrates.
Therefore, the protein requirement increased about 20 percent above the standard of Haecker.

Nutritive ratio: ratio of dig. Protein to the sum of digestible Carbohydrates (CF & NFE) and dig. Fat. Also called as albuminoid ratio.

NV = DCF + DNFE + (DEEx2.25) / DCP = TDN – DCP/ DCP

Where, TDN= DCF+DCP+DNFE+ (DEEx2.25)

Protein rich feeds: Narrow NV e.g. protein cakes.
Poor protein feeds: wider nutritive ratio e.g. roughages.

6. Morrison feeding standard

First presented in the 15^th edition of “Feeds and Feeding” published in 1915
Also called “Modified Wolff and Lehmann standard”.
These standards were expressed in terms of Dry Matter (D.M.), Digestible crude Protein (DCP) and Total Digestible Nutrients (TDN).
After revision, net energy values instead of TDN in computing rations were also included.
In the year 1956, Morrison included in the standard the allowances for calcium, Phosphorus and Carotene
The average of Morrison standards has been accepted for Indian livestock.

7. National Research Council (NRC) standard: First published in 1945

The standard includes digestible protein and total digestible nutrients (TDN)
Also includes the recommended requirements for calcium, phosphorus, carotene and vitamin D for most animals.
They use ME for poultry, DE for swine and horses, DE, ME and TDN for sheep, ME, TDN and NEm and NEg for beef cattle and for dairy cattle, values are given for DE, ME, TDN, NEm and NEg for growing animals with additional values as NEl for lactating cows.

8. Indian standards

Sen and Ray standards: he adopted the average of maximum and minimum values recommended by Morrison.
Indian Council of Agricultural Research: considered the fact that nutrient needs of livestock and poultry breeds under tropical environments are different from those developed in temperate climate.

C. PRODUCTION VALUE TYPE

1. Kellner feeding standard

Based upon “Starch” as a standard unit of measurement (Starch equivalent).

Starch equivalent:
Fat producing power of feed (A production type/ NE system).
SE of a feed is the number of Kg of starch that produces the same amount of fat as 100 kg of the test feed.
This starch equivalent in turn can be converted into energy by a method worked out by Armsby and Kellner.

2. Armsby feeding standard

Based on true protein and net energy values.

3. Agricultural Research Council (ARC) standard

Followed in the United Kingdom.
Give requirements of poultry, ruminants and pigs.

British Feeding Standards is that the unit of energy requirements has been expressed in terms of Starch equivalent instead of TDN or ME or NE as in Morrison and in N.R.C. standards.

5. Conservation of Feed through Silage and Hay

3.1 Storage

• Microbial and insect growth: Temp. 28-30 oC and 65-80% RH

• Insect spp.: Sitophilus oryzae (weevils); Oryzeaphilus (grain beetle); Tribolium (Flour beetle)

• Mould spp.: Aspergillus flavus; Aspergillus ochraceus; Fusarium; Penicillium spp.

• Temp range for fungi: above 25oC = Aspergillus and below 25oC = Fusarium spp.

• Mycotoxin: harmful chemicals produced by fungi.

• Aflatoxin: mutagenic and carcinogenic Aspergillus spp. (B1, B2, G1, G2) B1 (feed)- M1 (milk)

• Zearalenone: oestrogenic activity (pig), abortions Fusarium spp.

• Fumonisins: cardiotoxic Fusarium spp.

• Ochratoxin: nephrotoxic Penicillium spp.

• Safe level of aflatoxin: Poultry/dairy feed 20 ppb

Duck 3 ppb (Duck more sensitive)

• Mycotoxin management:

Methionine- detoxification
Ammonia treatment
Physical treatment sunlight (best method)
Mould inhibitor: formate and propionate (0.1-1.0%)
Binders: zeolites, aluminosilicates, bentonite, sepiolite
Antioxidants: Vit E, C
Enzymes: epoxidase, esterase

Microbes:

Eubacterium BBSH 797, C. sporogenes and L. viyulinus (Ochratoxin)

Trichosporan yeast (Zearalenone), Flavobacterium & A. repens (aflatoxin)

• Rodent control: warfarin, Comarin (Anticoagulant rodenticides)

• Fumigation:

• Ethylene dibromide

• 40% formalin (35ml) + 17.5 g KMnO4 per m3 for 20 min. = 2:1 (Max Exposure Limit = 2 ppm)

3.2 Conservation of Livestock Feed through Silage and Hay

Silage

Silage is the green succulent fermented material produced by controlled anaerobic fermentation of the green fodder crop retaining the high moisture content. It contains 25-35% DM & 14-16% CP. This process of making silage is called ensiling.

Selection of crops for silage making:

Thick stems
High level of fermentable sugar
Low protein like maize, sorghum, bajra etc.
Crop should have 35 % dry matter or 60-70% moisture at the time of ensiling.
Legumes are avoided because of containing high amounts of organic acids and anions which resist pH change.
Crop should be harvested between flowering and milk stage

Method of Silage making

A silo which is an air tight structure for storage and preservation.
One cubic meter space is required for 400kg fodder silage making.
Chopping of forage to a short length (1-3 cm).
Compact forage as tightly as possible.
Sprinkle salt at 0.5%, urea 1% and molasses 3% of the material weight to improve sugar content.
Maintain sealing for 45 days.

Types of fermentation during Silage formation

Lactic acid type- Desirable for making good quality silage and forage is carbohydrate rich. Sugars fermented to VFAs and lactic acid, low pH around 4 which inhibit the growth of undesirable bacteria to grow. It is mediated by Lactobacillus type bacteria .

Butyric acid type– When forage contains more protein and less carbohydrate than clostridium bacteria grow and deteriorate its quality. Butyric acid gives a sharp disagreeable smell which is not liked by animals.

Flieg index is used to evaluate silage quality which measures butyric acid produced. Lesser the butyric acid better will be silage quality.

Very good silage– greenish brown or golden color with acidic taste and is free from butyric acid with pH 3.5-4.2 and ammoniacal N < 10 % of total N .
Good silage– Brown color with acidic taste with <0.2% butyric acid and pH 4.2-4.5 and ammoniacal-N 10-15% of total N.
Fair silage- pH 4.5-4.8, >0.2 % butyric acid, ammoniacal –N 15-20% of total.

Hay-

Hay is obtained by cutting and curing (sun drying) the fine stemmed grasses or legumes so that moisture content is not more than 12-14%.

Crop–

Forages like rasses & legumes
Harvested at 2/3rd flowering stage at early in the morning to minimize loss of leaves

Methods of Hay making

Field curing– sun drying.

Steps includes

Cutting crop- left as such to dry partially
Swath curing to obtain moisture upto 40%
Raking –obtained foarge after wilting of foarge to 40% make loose cylindrical bundles
Cocking-making bigger heaps of cured hay
Baling – by using baler attached to tractor into tightly packed stacked
Storing
Barn drying: using air to reduce moisture to 20-25%. Much greener and leafy

3. Artificial drying-hot air-expensive Rapid drying Types of hay

Legume hay: higher TDN and DCP and are rich in protein & minerals. Crops –Lucerne, Cowpea, Berseem. Good quality hay.

Non legume hay: less palatable and less amount of protein, vitamin and nutrients than legume hay but rich in carbohydrates. Crops – Oat, barley, Bajra, sorghum and grasses.

Mixed hay: The nutritive value of mixed hay depends upon the type of legume and non legume crops.

Losses of nutrients during hay making

Losses by shattering– due to shattering of leaves. To avoid this hay should be field cured in morning hours rather than during warm periods of day.
Losses of vitamins due to oxidation– during drying carotene which is a source of vitamin A in green plants is bleached hence decrease in vitamin A content of hay.
Losses due to fermentation– after harvesting the crop plant enzymes act on soluble carbohydrates and form co2 and water. Proteins are hydrolysed to amino acids.
Losses due to leaching– if hay is almost cured and exposed to heavy rains then leaching of nutrients like soluble carbohydrate and protein occurs.

Total loss estimated in hay making

Loss of DM – 20-30% in legumes and

10-15% in grasses

Loss of protein – 28%
Loss of carotene- 90%
Loss of energy – 25%

Changes during storage- sometime when crops cured for hay making retains higher moisture level during stacking it produces much heat which change the color of hay to dark brown color due to oxidative degradation of sugars combining with amino acids or proteins and is called as Mow Burnt/ brown hay.

Difference in silage and Hay

particular	silage	Hay
DM (%)	30-35	10-15
Type of crop	Non leguminous type. Maize,jowar,sorghum, bajra	Leguminous type Lucerne, oats berseem
Texture OF CROP	Thick stemmed, carbohydraterich	Thin stemmed, protein rich
Method utilised	Fermented product	Sun dried product
Losses of nutrients	less	more
Time of harvest of crop	between flowering and milk stage	2/3rd flowering stage
digestibility	Partially digested during fermentation so more digestible	Not digested during drying. Less digestible.
Drying	Crop is not dried and used aftercutting only	it is dried first
Air	Complete exclusion of air	Openly dried in air

Haylage (hay+silage): Dry matter in crops used for haylage making is 40- 45%.
Wastelage: Anaerobically fermented animal waste like poultry droppings, poultry litter, swine excreta and bovine dung along with other feed ingredients with the help of lactic acid producing bacteria.
Oat hay poisoning/ nitrate poisoning: Nitrate poisoning can occur in crops like sorghum, lucerne, and Sudan grass. In the rumen, nitrate is reduced to nitrite, which, when absorbed into the bloodstream, oxidizes the ferrous ion in hemoglobin to ferric ion, forming methemoglobin. This causes the blood to become chocolate brown, leading to a brownish discoloration of the mucous membranes and skin.

Quizzes

Unit 4 Animal Nutrition Quiz

Karnataka Veterinary Medical Officer Course

August, 2024

Participants 11

Unit 4 Animal Nutrition

ajmi bin azeez August 20, 2024

1. Processing of Concentrates

2. Processing of Roughages

3. Feeding Experiments

4. Feeding Standards

5. Conservation of Feed through Silage and Hay